diff --git a/actions/conversation.php b/actions/conversation.php
index 637e86e4b2..aa2539d213 100644
--- a/actions/conversation.php
+++ b/actions/conversation.php
@@ -123,9 +123,15 @@ class ConversationAction extends Action
      */
     function showContent()
     {
-        $tnl = new FullThreadedNoticeList($this->notices, $this, $this->userProfile);
+        $user = common_current_user();
 
-        $cnt = $tnl->show();
+        if (!empty($user) && $user->conversationTree()) {
+            $nl = new ConversationTree($this->notices, $this);
+        } else {
+            $nl = new FullThreadedNoticeList($this->notices, $this, $this->userProfile);
+        }
+
+        $cnt = $nl->show();
     }
 
     function isReadOnly()
@@ -162,3 +168,4 @@ class ConversationAction extends Action
                               _('Conversation feed (Activity Streams JSON)')));
     }
 }
+
diff --git a/lib/conversationtree.php b/lib/conversationtree.php
new file mode 100644
index 0000000000..49ed48af20
--- /dev/null
+++ b/lib/conversationtree.php
@@ -0,0 +1,215 @@
+<?php
+/**
+ * StatusNet - the distributed open-source microblogging tool
+ * Copyright (C) 2011, StatusNet, Inc.
+ *
+ * Conversation tree widget for oooooold school playas
+ * 
+ * PHP version 5
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Widget
+ * @package   StatusNet
+ * @author    Evan Prodromou <evan@status.net>
+ * @copyright 2011 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
+ * @link      http://status.net/
+ */
+
+if (!defined('STATUSNET')) {
+    // This check helps protect against security problems;
+    // your code file can't be executed directly from the web.
+    exit(1);
+}
+
+/**
+ * Conversation tree
+ *
+ * The widget class for displaying a hierarchical list of notices.
+ *
+ * @category Widget
+ * @package  StatusNet
+ * @author   Evan Prodromou <evan@status.net>
+ * @license  http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
+ * @link     http://status.net/
+ */
+class ConversationTree extends NoticeList
+{
+    var $tree  = null;
+    var $table = null;
+
+    /**
+     * Show the tree of notices
+     *
+     * @return void
+     */
+    function show()
+    {
+        $cnt = $this->_buildTree();
+
+        $this->out->elementStart('div', array('id' =>'notices_primary'));
+        // TRANS: Header on conversation page. Hidden by default (h2).
+        $this->out->element('h2', null, _('Notices'));
+        $this->out->elementStart('ol', array('class' => 'notices xoxo'));
+
+        if (array_key_exists('root', $this->tree)) {
+            $rootid = $this->tree['root'][0];
+            $this->showNoticePlus($rootid);
+        }
+
+        $this->out->elementEnd('ol');
+        $this->out->elementEnd('div');
+
+        return $cnt;
+    }
+
+    function _buildTree()
+    {
+        $cnt = 0;
+
+        $this->tree  = array();
+        $this->table = array();
+
+        while ($this->notice->fetch()) {
+
+            $cnt++;
+
+            $id     = $this->notice->id;
+            $notice = clone($this->notice);
+
+            $this->table[$id] = $notice;
+
+            if (is_null($notice->reply_to)) {
+                $this->tree['root'] = array($notice->id);
+            } else if (array_key_exists($notice->reply_to, $this->tree)) {
+                $this->tree[$notice->reply_to][] = $notice->id;
+            } else {
+                $this->tree[$notice->reply_to] = array($notice->id);
+            }
+        }
+
+        return $cnt;
+    }
+
+    /**
+     * Shows a notice plus its list of children.
+     *
+     * @param integer $id ID of the notice to show
+     *
+     * @return void
+     */
+    function showNoticePlus($id)
+    {
+        $notice = $this->table[$id];
+
+        $this->out->elementStart('li', array('class' => 'hentry notice',
+                                             'id' => 'notice-' . $id));
+
+        $item = $this->newListItem($notice);
+        $item->show();
+
+        if (array_key_exists($id, $this->tree)) {
+            $children = $this->tree[$id];
+
+            $this->out->elementStart('ol', array('class' => 'notices'));
+
+            sort($children);
+
+            foreach ($children as $child) {
+                $this->showNoticePlus($child);
+            }
+
+            $this->out->elementEnd('ol');
+        }
+
+        $this->out->elementEnd('li');
+    }
+
+    /**
+     * Override parent class to return our preferred item.
+     *
+     * @param Notice $notice Notice to display
+     *
+     * @return NoticeListItem a list item to show
+     */
+    function newListItem($notice)
+    {
+        return new ConversationTreeItem($notice, $this->out);
+    }
+}
+
+/**
+ * Conversation tree list item
+ *
+ * Special class of NoticeListItem for use inside conversation trees.
+ *
+ * @category Widget
+ * @package  StatusNet
+ * @author   Evan Prodromou <evan@status.net>
+ * @license  http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
+ * @link     http://status.net/
+ */
+class ConversationTreeItem extends NoticeListItem
+{
+    /**
+     * start a single notice.
+     *
+     * The default creates the <li>; we skip, since the ConversationTree
+     * takes care of that.
+     *
+     * @return void
+     */
+    function showStart()
+    {
+        return;
+    }
+
+    /**
+     * finish the notice
+     *
+     * The default closes the <li>; we skip, since the ConversationTree
+     * takes care of that.
+     *
+     * @return void
+     */
+    function showEnd()
+    {
+        return;
+    }
+
+    /**
+     * show link to notice conversation page
+     *
+     * Since we're only used on the conversation page, we skip this
+     *
+     * @return void
+     */
+    function showContext()
+    {
+        return;
+    }
+
+    /**
+     * show people this notice is in reply to
+     *
+     * Tree context shows this, so we skip it.
+     *
+     * @return void
+     */
+    function showAddressees()
+    {
+        return;
+    }
+}